User Manual

MPU-6000/MPU-6050 Register Map and
Descriptions
Document Number: RM-MPU-6000A-00
Revision: 4.2
Release Date: 08/19/2013
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Each enabled slave will have EXT_SENS_DATA registers associated with it by number of bytes read
(I2C_SLVx_LEN) in order of slave number, starting from EXT_SENS_DATA_00. Note that this
means enabling or disabling a slave may change the higher numbered slaves’ associated registers.
Furthermore, if fewer total bytes are being read from the external sensors as a result of such a
change, then the data remaining in the registers which no longer have an associated slave device
(i.e. high numbered registers) will remain in these previously allocated registers unless reset.
If the sum of the read lengths of all SLVx transactions exceed the number of available
EXT_SENS_DATA registers , the excess bytes will be dropped. There are 24 EXT_SENS_DATA
registers and hence the total read lengths between all the slaves cannot be greater than 24 or some
bytes will be lost.
Note: Slave 4’s behavior is distinct from that of Slaves 0-3. For further information regarding the
characteristics of Slave 4, please refer to Registers 49 to 53.
Example:
Suppose that Slave 0 is enabled with 4 bytes to be read (I2C_SLV0_EN = 1 and I2C_SLV0_LEN =
4) while Slave 1 is enabled with 2 bytes to be read, (I2C_SLV1_EN=1 and I2C_SLV1_LEN = 2). In
such a situation, EXT_SENS_DATA _00 through _03 will be associated with Slave 0, while
EXT_SENS_DATA _04 and 05 will be associated with Slave 1.
If Slave 2 is enabled as well, registers starting from EXT_SENS_DATA_06 will be allocated to Slave
2.
If Slave 2 is disabled while Slave 3 is enabled in this same situation, then registers starting from
EXT_SENS_DATA_06 will be allocated to Slave 3 instead.
Register Allocation for Dynamic Disable vs. Normal Disable
If a slave is disabled at any time, the space initially allocated to the slave in the EXT_SENS_DATA
register, will remain associated with that slave. This is to avoid dynamic adjustment of the register
allocation.
The allocation of the EXT_SENS_DATA registers is recomputed only when (1) all slaves are
disabled, or (2) the I2C_MST_RST bit is set (Register 106).
This above is also true if one of the slaves gets NACKed and stops functioning.